Conventionally, there has been known a technique of performing a high-accuracy diagnosis of an object by combining images of the object obtained by various types of diagnostic schemes. It is known, in particular, that combining a structure such as a bone or organ obtained from computed tomography (CT) with functional information obtained from magnetic resonance imaging (MRI) can provide high utility for, for example, surgical operation support.
As a technique of this type, there is available a fusion technique of complementarily presenting information by superimposing and displaying a plurality of images. For example, there is generally known a display method of fusing a morphological image of the coronary artery obtained from coronary arteriography CT with a functional image of myocardial perfusion obtained from positron emission tomography (PET). When a morphological image of the coronary artery is fused with a functional image of myocardial perfusion, a display method using volume rendering is generally used.
The above fusion display makes it easy to understand the relationship between a morphological defect (for example, coronary stenosis) and a functional defect (for example, myocardial ischemia).
The above fusion display based on volume rendering provides good visibility when it comes to overview. However, this technique makes it difficult to grasp the positional relationship between morphological information and functional information when paying attention to a specific region (for example, a coronary stenosis site), or requires a cumbersome operation for volume rotation or the like. In an actual diagnosis, MPR display is more common than volume rendering when performing detailed observation.